Beechcraft C-12C Operator And Technical Reference Manual page 248

TM 1-1510-218-10
(c) BOTH.
transmitter, and guard receiver.
(d) ADF.
system, if installed, and main receiver.
c. Normal Operation.
(1) Turn On Procedure.
1. Function selector switch, UHF control
panel – BOTH.
(2) Receiver Operating Procedure.
The PRESET channel selector and manual
frequency selectors are inoperative when
the MANUAL / PRESET / GUARD switch is
set to GUARD.
1. Function
required.
2. Frequency
frequency using either preset channel
control or manual frequency selector
controls.
3. Volume – Adjust.
4. SQUELCH – As required.
(3) Transmitter Operating Procedure.
1. Transmitter selector switch – UHF
position.
2. Microphone switch – Press.
(4) Shutdown Procedure.
1. Function selector switch – OFF.
d. Emergency Operation.
Transmission on emergency frequencies
(guard channel) shall be restricted to
emergencies only.
frequency of 121.500 MHz is also available
on the VHF command radio set.
1. Transmitter selector switch – UHF
position.
2. Mode selector switch – GUARD.
3A-6
Selects main receiver,
Selects ADF or homing
NOTE
selector switch
– Select required
NOTE
An emergency
3A-8. UHF
HAVE QUICK).
a. Description.
line-of-sight
transmission and reception of AM signals in the ultra
high frequency range of 225.000 to 399.975 MHz for a
distance range of approximately 50 miles. Channel
selection is spaced at 0.025 MHz. A separate receiver
is incorporated to provide monitoring capability for the
UHF guard frequency (243.0 MHz). UHF audio output
is applied to the audio panel where it is routed to the
headsets.
The PRESET channel selector and manual
frequency selectors are inoperative when
the mode selector is set to GUARD
position. The receiver-transmitter will be
– As
set to the emergency frequency only.
Existing capabilities of the HAVE QUICK
modified radio are preserved to the maximum extent
possible when it is operated in the normal (non-
hopping) mode. No new procedures are required for
normal radio operation.
To operate in the AM mode, the radio must first
be initialized. This initialization requires the setting of
two control entries into the radio, Word of Day (WOD)
and Time of Day (TOD). The WOD defines the choice
of frequency hopping pattern for the day. The WOD
choice is a managerial function and the same WOD
may be used for one or more days. The TOD must be
loaded into the clock contained within the radio.
The transmitter and receiver sections of the UHF
unit operate independently, but share the same power
supply and frequency control circuit. Separate cables
route transmit and receive signals to their respective
receiver/transmitter.
The UHF command set is protected by a
5-ampere UHF circuit breaker in the overhead circuit
breaker panel. Refer to Figure 2-16, Sheets 1 and 2.
The associated blade type antenna is shown in Figure
2-1.
b. Controls and Functions.
3A-3.
(1) Manual
(Hundredths). Selects hundredths digit of frequency
(2, 3, A or T) in MHz.
3. Microphone switch – Press.
COMMAND SET
The UHF command set is a
radio transceiver
NOTE
Frequency
(AN/ARC-164
that provides
Refer to Figure
Selector Switch